System and method for electroplating flexible substrates

ABSTRACT

A processing system for processing flexible substrates is disclosed. The system includes a loading station having an input spool adapted to support a wounded, unprocessed flexible substrate; a processing station adapted to perform one or more predetermined processes on the flexible substrate; an unloading station having an output spool adapted to receive the processed flexible substrate; and a substrate stability subsystem adapted to maintain the flexible substrate in a substantially vertical orientation while the substrate undergoes the one or more processes performed by the processing station. The substrate stability subsystem includes movable upper clips adapted to engage with upper portions of the flexible substrate, and a plurality of lower clips adapted to engage with lower portions of the flexible substrate as it is being transported into and out of the processing station. Also disclosed is a unique shield for the cathode clips to improve the uniformity of the deposition formed on the flexible substrate, and a unique seal to allow the transportation of the lower clips into and out of the electroplating cell while reducing leakage of fluid from the cell.

FIELD OF THE INVENTION

This invention relates generally to electroplating systems, and in particular, to a system and method for electroplating flexible substrates.

BACKGROUND OF THE INVENTION

The electroplating of a flexible substrate typically involves a two step process. First, an electrically-conductive seed layer is formed on the flexible substrate. Typically, this is accomplished by subjecting the substrate to a vacuum sputtering process to form a thin layer of metallization on the substrate (typically referred to as a “seed layer”). For example, a copper seed layer having a thickness between 500 and 2000 Angstroms may be formed on a polyimide or polyethylene substrate. The seed layer serves as an electrically-conductive layer on which further deposition may be formed by a subsequent electroplating process.

Second, the flexible substrate having the seed layer thereon is subjected to an electroplating process to increase the thickness of the metallization layer to a desired level. In some systems, the flexible substrate is fed into an electroplating apparatus in a vertical orientation. Near a loading station, electrically-conductive clips make contact to upper portions of the flexible substrate in order to provide a cathode potential to the substrate. The flexible substrate is transported horizontally from the loading station, through one or more pre-treatment cells, one or more electroplating cells, and one or more post-treatment cells, to an unloading station. This process and equipment are further explained with reference to the following example.

FIG. 1A illustrates a top view of a conventional electroplating system 100 for electroplating flexible substrates. The electroplating system 100 includes a loading station 102, a pre-treatment cell 104, an electroplating cell 106, a post-treatment cell 108, and an unloading station 110. The electroplating system 100 further includes a substrate transportation subsystem 120 including an input spool 122 oriented to have a vertical rotational axis, an output spool 124 also oriented to have a vertical rotational axis, and a drive motor (not shown) to cause the rotation of the input and output spools such that the flexible substrate S is transported laterally from the input spool 122 to the output spool 124 by way of the pre-treatment cell 104, electroplating cell 106, and post-treatment cell 108.

The conventional electroplating system 100 further includes a cathode contact system 140 comprising an idle wheel 142 oriented to have a vertical rotational axis, a drive wheel 144 also oriented to have a vertical rotational axis, and an electrically-conductive belt 146 situated around and adapted to rotate in the counter-clockwise direction with the idle and drive wheels 142 and 144. The drive motor that drives the substrate transportation system 120 may also serve to drive the cathode contact system such that the movement of both are in synchronization. The belt 146 supports a plurality of equally spaced-apart, electrically-conductive clips 148 adapted to make cathode contact to upper portions of the flexible substrate S while it travels from the loading station 102 to the unloading station 110. The electroplating system 100 further includes a clip strip cell 112 adapted to remove residual plating which forms on the clips during the electroplating process.

In operation, the drive motor is operated to cause the clockwise movement of the drive wheel 124 of the substrate transportation system 120, and the counter-clockwise movement of the cathode contact system 140 such that the movement of both subsystems 120 and 140 are in synchronization. Near the loading station 102, the clips 148 are operated to engage the top portion of the flexible substrate S. The clips 148 move in synchronization with the flexible substrate S maintaining a fixed cathode contact to the flexible substrate S as it moves from the loading station 102 to the unloading station 110. The substrate S undergoes the various processes provided by the pre-treatment cell 104, electroplating cell 106, and post-treatment cell 108, wherein the clips 148 provide the cathode contact for the electroplating process. Near the unloading station 110, the clips 148 are operated to disengage from the substrate S, and subsequently move to the clip strip cell 112 for removal of residual plating formed on the clips 148. The processed substrate S is continuously rolled onto the output spool 124.

FIG. 1B illustrates a side view of the conventional electroplating cell 106 including a normally situated flexible substrate S. The conventional cell 106 includes a container 150 adapted to support a bath of electroplating fluid 152, one or more anode electrodes 154 situated within the container 150 and adapted to make contact with the plating fluid bath 152, and a sparger 156 adapted to introduce fresh plating fluid into the plating fluid bath 152 in the direction of the substrate S. In normal operations, the flexible substrate S is oriented substantially vertical within the electroplating cell 106. Generally, the weight of the flexible substrate S keeps it substantially vertical.

FIG. 1C illustrates a side view of a conventional electroplating cell 106 including an abnormally situated flexible substrate S. When the thickness of the flexible substrate S becomes relatively small, the stability of the substrate S as it travels through the electroplating cell 106 typically degrades. As a result, the orientation of the flexible substrate S is no longer substantially vertical, and may warp as shown. Since the spatial distance between the anode 154 and the flexible substrate S is no longer consistent due to the warping of the substrate S, a non-uniform plating forms on the surface of the flexible substrate S.

FIG. 1D illustrates a side view of the conventional electroplating cell 106 including another abnormally situated flexible substrate S. Another problem associated with thin flexible substrates is that the bottom portion of the substrate tends to float. As shown, the bottom portion of the flexible substrate S curves upwardly due to the buoyancy of the substrate S. Similarly, because the spatial distance between the anode 154 and the flexible substrate S is no longer consistent due to the buoyancy of the substrate S, a non-uniform plating forms on the surface of the flexible substrate S.

In the past, some electroplating systems, especially those designed and manufactured in Japan and Korea, include cathode contact rollers located at the entrance and exit of an electroplating cell. The contact rollers maintain the material in a vertical orientation while providing a cathode contact to the material. These cathode contact rollers need to be located at intervals along the length of the flexible substrate. Typically, the cathode contact rollers are designed to provide a cathode potential to about two (2) meters length of material. Normally, the effective cell length range from 10 to 30 meters. Accordingly, five (5) to 15 electroplating cells need to be provided to effectively plate 10 to 30 meters of material, which translates to five (5) to 15 sets of cathode contact rollers along the length of the material. The large number of cathode contact rollers making contact to the substrate typically causes considerable damage to the material.

SUMMARY OF THE INVENTION

A processing system for processing flexible substrates or other types of articles is disclosed. The system includes a loading station having an input spool adapted to provide an unprocessed flexible substrate; a processing station adapted to perform one or more predetermined processes on the flexible substrate; an unloading station having an output spool adapted to receive the processed flexible substrate; and a substrate stability subsystem adapted to maintain the flexible substrate in a substantially stable vertical orientation while the substrate undergoes the one or more processes performed by the processing station. The substrate stability subsystem includes a plurality of movable upper clips adapted to engage with respective upper portions of the flexible substrate, and a plurality of movable lower clips adapted to engage with respective lower portions of the flexible substrate as it is being transported into and out of the processing station. Also disclosed is a unique shield for the cathode clips to improve the uniformity of the deposition formed on the flexible substrate, and a unique seal to allow the transportation of the lower clips into and out of a processing cell while reducing leakage of fluid from the cell.

Other aspects, features, and techniques of the invention will be apparent to one skilled in the relevant art in view of the following detailed description of the exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a top view of a conventional electroplating system for electroplating flexible substrates;

FIG. 1B illustrates a side view of a conventional electroplating cell including a normally situated flexible substrate;

FIG. 1C illustrates a side view of a conventional electroplating cell including an abnormally situated flexible substrate;

FIG. 1D illustrates a side view of a conventional electroplating cell including another abnormally situated flexible substrate;

FIG. 2A illustrates a top view of an exemplary electroplating system in accordance with an embodiment of the invention;

FIG. 2B illustrates a side view of an exemplary electroplating cell in accordance with another embodiment of the invention;

FIG. 3A illustrates a right side view of the exemplary substrate stability subsystem in accordance with another embodiment of the invention;

FIG. 3B illustrates a left side view of the exemplary substrate stability subsystem in accordance with another embodiment of the invention;

FIG. 4A illustrates a front view of an exemplary upper clip in accordance with another embodiment of the invention;

FIG. 4B illustrates a side view of the exemplary upper clip in accordance with another embodiment of the invention;

FIG. 5A illustrates a side view of an exemplary lower clip in a closed position in accordance with another embodiment of the invention;

FIG. 5B illustrates a side view of the exemplary lower clip in an open position in accordance with another embodiment of the invention;

FIG. 6 illustrates a front view of the exemplary upper and lower clips engaged with a flexible substrate in accordance with another embodiment of the invention;

FIG. 7A illustrates a side view of an exemplary seal in accordance with another embodiment of the invention;

FIG. 7B illustrates a front view of the exemplary seal in accordance with another embodiment of the invention; and

FIG. 7C illustrates a top view of the exemplary seal in accordance with another embodiment of the invention;

FIG. 7D illustrates a top view of the lower portion of the exemplary seal in accordance with another embodiment of the invention;

FIG. 7E illustrates a side view of the lower portion of the exemplary seal in accordance with another embodiment of the invention; and

FIG. 7F illustrates a front view of the lower portion of the exemplary seal in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 2A illustrates a top view of an exemplary electroplating system 200 in accordance with an embodiment of the invention. The electroplating system 200 is particularly useful for electroplating a flexible substrate S. The flexible substrate S includes a seed layer disposed on either or both its sides. The electroplating system 200 forms one or more metallization layers on top of the seed layer by one or more electroplating processes, respectively. The flexible substrate S is fed into the electroplating system in a substantially vertical orientation.

As discussed in more detail below, the electroplating system 200 comprises a unique substrate stability subsystem including upper and lower clips adapted to engage upper and lower portions of the flexible substrate S to maintain the substrate in a substantially stable vertical orientation as it moves through the various processing cells. Accordingly, the substrate stability subsystem maintains the flexible substrate S a predetermined distance from the anode electrode to ensure a desirable uniformity of the plating deposition on the surface of the flexible substrate S. Another feature of the electroplating system 200 includes a unique seal for the electroplating cell that allows the passage of the lower clips into and out of the cell, while reducing leakage of plating fluid from the cell. Additionally, in the case where the upper and/or lower clips also function as a cathode contact to the flexible substrate S, the electroplating system 200 includes a clip shield adapted to further improve the uniformity of the plating deposition on surface of the flexible substrate S.

In particular, the electroplating system 200 comprises a loading station 202, one or more pre-treatment cells 204, one or more electroplating cells 206, and one or more post-treatment cells, including a post-treatment wet cell 210 and a post-treatment drying cell 212, and an unloading station 214. The electroplating system 200 further comprises a substrate stability subsystem 250 adapted to maintain the flexible substrate S in a substantially stable vertical orientation as the flexible substrate S travels through the various processing cells. The substrate stability subsystem 250 may also serve to provide a continuous cathode contact to the flexible substrate S as it travels through the various processing cells.

More specifically, the loading station 202 comprises an input spool 202 a around which the unprocessed, flexible substrate S is wound, and one or more tension rollers 202 b and 202 c to apply tension to the flexible substrate S, and also guide the flexible substrate S toward the processing area of the electroplating system 200. In this example, the input spool 202 a and the tension rollers 202 b and 202 c are oriented such that their respective rotational axes extend substantially vertical. Although only two tension rollers 202 b and 202 c are shown, it shall be understood that the electroplating system 200 may include more or less tension rollers. The number of tension rollers needed depends on the thickness, physical size, and weight of the substrate material, so that the material properly unwinds from the input spool 202 a.

The pre-treatment cell 204 is adapted to perform one or more pre-treating processes on the flexible substrate S prior to it undergoing the electroplating processes performed by the electroplating cell 206. The purpose of the pre-treatment cell 204 is to clean and remove oxides (e.g., copper oxides) from the flexible substrate S before the substrate S undergoes the electroplating processes performed by the electroplating cell 206. Such pre-treating processes may include an alkaline cleaning, acid cleaning, a de-ionized (DI) water rinsing, and/or others.

The electroplating cell 206 is adapted to perform one or more electroplating processes to form one or more metallization layers on the flexible substrate S. For example, the electroplating cell 206 may be configured to perform an electroplating process to form a layer of copper (Cu) on the flexible substrate S. In this example, the electroplating cell 206 is U-shaped to reduce the overall length of the electroplating system 200.

As discussed in more detail below, the substrate stability subsystem 250 includes lower clips that engage with lower portions of the flexible substrate S as it moves into and out of the electroplating cell 206. In the electroplating cell 206, which performs electroplating of the flexible substrate S by immersing it in a bath of plating fluid, the lower clips traverse a bottom portion of the liquid bath. As discussed in more detail below, the electroplating cell 206 includes input and output seals 205 a and 205 b that allows the passage of the lower clips into and out of the electroplating cell 206, while reducing the amount of leakage. Some leak will occur, though. Accordingly, the electroplating cell 206 also includes an input drain 206 a and an output drain 206 b to receive the leakage of the plating fluid through the entrance and exit openings.

The post-treatment wet cell 210 is adapted to perform one or more post-treating processes on the flexible substrate S after it has undergone the electroplating processes performed by the electroplating cell 206. The purpose of the “wet” post-treating process is to remove residual plating fluid left on the flexible substrate S from the prior electroplating process, and to apply an anti-tarnish protective coating. Such post-treating processes may include an acid rinse, a DI water rinse, an anti-tarnish rinse, a warm DI water rinse, and/or others. After the post-treatment cell 210, the flexible substrate S is subjected to a drying process performed by the post-treatment dry cell 212. The purpose of the drying process is to substantially dry the flexible substrate S before it goes into the unloading station 214.

The unloading station 214 comprises an output spool 214 a around which the processed flexible substrate S is wound, and one or more tension rollers 214 b and 214 c to apply tension to the flexible substrate S, and also guide the flexible substrate S from the processing area to the output spool 214 a. In this example, the output spool 214 a and the tension rollers 214 b and 214 c are oriented such that their respective rotational axes extend substantially vertical. Although only two tension rollers 214 b and 214 c are shown, it shall be understood that the electroplating system 200 may include more or less tension rollers, as discussed above with reference to the tension rollers of the loading station.

A drive motor may be coupled to the input and output spools 202 a and 214 a (as well as the tension rollers 202 b-c and 214 b-c) to cause the rotation thereof in order to transport the flexible substrate S from the loading station 202 to the unloading station 214 by way of the various processing cells of the electroplating system 200.

The substrate stability subsystem 250 comprises upper and lower, movable support structures 252 a and 252 b (e.g., a belt, cable, chain, etc.) adapted to respectively support a plurality of upper and lower clips 254 a and 254 b. The upper and lower, support structures 252 a and 252 b are positioned around a plurality of conveyor wheels (e.g., upper wheels 256 a, 258 a, and 260 a) and (e.g., lower wheels 256 b and 258 b). As discussed in more detail below, the upper and lower conveyor wheels are coupled to one or more drive motors for rotating the upper and lower wheels along with the upper and lower support structures 252 a and 252 b in a counter-clockwise direction. The drive motor for the substrate stability subsystem 250 may be the same or different than the drive motor for the transportation of the flexible substrate S. If different, the drive motors would be synchronized together so that the flexible substrate S moves at substantially the same speed as the support structures 252 a and 252 b.

As discussed in more detail below, the upper and lower clips 254 a and 254 b of the substrate stability subsystem 250 engage with upper and lower portions of the flexible substrate S to maintain the substrate S in a substantially vertical orientation as the substrate S moves through the various processing cells of the electroplating system 200. This helps to improve the uniformity of the plating formed on the surface of the flexible substrate S by keeping the substrate S substantially fixed with respect to the anode. The upper and lower clips 254 a and 254 b may be configured to be substantially equally spaced along the upper and lower support structures 252 a and 252 b, respectively. The spacing between adjacent clips may be, for example, three (3) to six (6) inches. In general, the spacing may depend on the width of the flexible substrate S and the desired current density.

In addition to applying vertical tension to the flexible substrate S, the upper and lower clips 254 a and 254 b may be used to apply a cathode contact to the flexible substrate S. In this regard, a cathode potential may be applied to the upper and/or lower support structures 252 a and 252 b in order to provide a cathode potential to the upper and/or lower clips 254 a and 254 b. Accordingly, the upper and/or lower support structures 252 a and 252 b along with the upper and/or lower clips 254 a and 254 b may be made of an electrically-conductive material (e.g., a metal). In this example, only the upper clips are used to provide a cathode contact to the flexible substrate S. The plating of the substrate S may cause residual plating to form on the upper clips 254 a. Thus, the electroplating system 200 further includes a clip strip cell 262 to remove residual plating off of the upper clips 254 a.

In operation, the drive motor of the substrate transportation system is operated to transport the flexible substrate S from the loading station 202 to the unloading station 214 through the various processing cells 204, 206, 210, and 212 of the electroplating system 200. If separate, the drive motor of the substrate stability system 250 is also operated to cause the upper and lower support structures 252 a and 252 b including the upper and lower clips 254 a and 254 b to move substantially in synchronous with the flexible substrate S. At a region immediately downstream of the loading station 202, the upper clips 254 a are operated to engage the flexible substrate S. At a region immediately downstream of the region in which the upper clips 254 a first engage the flexible substrate S, the lower clips 254 b are operated to engage the flexible substrate S. Having the upper clips 254 a engage the flexible substrate S prior to the lower clips 254 b, prevents sagging of the flexible substrate S. This is because the substrate S is allowed to be initially suspended by the upper clip and therefore the weight of the material prevents it from sagging; then the lower clip is allowed to engage the suspended substrate S.

After the upper and lower clips 254 a and 254 b are engaged with the flexible substrate S, the clips and the substrate S move substantially together through the various processing cells of the electroplating system 200. While in transit, the upper and lower clips 254 a and 254 b apply vertical tension to the substrate S so that the flexible substrate S remains substantially vertically oriented within the various processing cells, and in particular, within the electroplating cell 206. As previously discussed, the stable, vertical orientation of the flexible substrate S improves the uniformity of the plating deposition across the substrate S. In addition, as previously discussed, the upper and/or lower clips 254 a and 254 b may also serve as a cathode contact to the flexible substrate S while the substrate S undergoes an electroplating process within the electroplating cell 206.

At a region downstream of the post-treatment dry cell 212, the upper and lower clips 254 a and 254 b clips disengage from the flexible substrate S to allow it to be unloaded onto the output spool 214 a in the unloading station 214. In this example, the upper and lower clips 254 a and 254 b disengage from the flexible substrate S at substantially the same region (e.g., at substantially the same time). Alternatively, the upper and lower clips 254 a and 254 b may be disengaged at a location upstream of the post-treatment cell. In this manner, the clips would not contaminate the substrate S by allowing drainage to contaminate the plating finish on the substrate S. The upper clips 254 a are subsequently transported into the clip strip cell 262 to remove residual plating formed thereon during the electroplating process.

FIG. 2B illustrates a side view of an exemplary electroplating cell 206 in accordance with another embodiment of the invention. The electroplating cell 206 comprises a container 220 adapted to support a bath of plating fluid 224, one or more anode electrodes 226 situated within the container 220 and adapted to make contact with the plating fluid bath 224, and a sparger 228 adapted to introduce fresh plating fluid into the plating fluid bath 224 in the direction of the substrate S. As illustrated in this figure, the upper and lower clips 254 a and 254 b are engaged with upper and lower portions of the flexible substrate S to ensure that the substrate S is oriented substantially vertical within the electroplating cell 206. As previously discussed, this improves the uniformity of the plating deposition across the flexible substrate S.

FIG. 3A illustrates a right side view of the exemplary substrate stability subsystem 250 in accordance with another embodiment of the invention. As shown, the substrate stability subsystem 250 comprises an upper drive motor 274, an upper gear reducer 276, a drive shaft 278, the upper drive wheel 256 a, the lower idle wheel 256 b, a turning drum 280, the upper supporting structure 252 a (in this example, a belt) supporting a plurality of the upper clips 254 a, and the lower supporting structure 252 b (in this example, a belt) supporting a plurality of the lower clips 254 b. The upper gear reducer 276 reduces the rotational speed of the drive shaft 278 as compared to the rotational speed of the upper drive motor 274. The drive shaft 278 is rotatably coupled to the upper drive wheel 256 a and turning drum 280, and may extend coaxially through the lower idle wheel 256 b and separated therefrom by a bearing. The upper drive wheel 256 a assists in the movement of the upper supporting structure 256 a including the upper clips 254 a thereon. The lower idle wheel 256 b assists in the movement of the lower supporting structure 256 b including the lower clips 254 b thereon. The turning drum 208 laterally supports the flexible substrate S through the turn.

FIG. 3B illustrates a left side view of the exemplary substrate stability subsystem 250 in accordance with another embodiment of the invention. The substrate stability subsystem 250 further comprises the upper idle wheel 260 a, which rotates around a shaft 282. The substrate stability subsystem 250 further comprises the lower drive wheel 252 b rotatably coupled to a lower drive motor 290 by way of a gear reducer 292. The lower drive motor 290 may be coupled to the upper drive motor 272 by way of servos and/or encoders, so that the movement of the upper and lower belts 252 a and 252 b are substantially synchronous. In this example, the upper drive motor 272 may serve as the master which sets the speed for the bottom conveyor as well as the speed for the conveyor that transports the flexible substrate S. Similar to the upper clips 254 a, the lower clips 254 b are spring-biased in the closed position, and opened by a clip actuator at any desired location along their movement.

FIGS. 4A-4B illustrate front and side views of an exemplary upper clip 400 in accordance with another embodiment of the invention. The clip 400 may be a detailed version of the upper clip 254 a discussed above. In particular, the clip 400 comprises a fixed member 402 including an upper back end for attaching to the upper supporting structure 252 a, an upper front end attached to an end of a torsional spring 404, and a lower end attached to a first clip member 406. The first clip member 406 includes a first lip 408 at its lower end for making contact to one side of the flexible substrate S. As shown in FIG. 4A, the sides of the first clip member 406 are tapered, such that its upper end is wider than its lower end.

The clip 400 further comprises a pivoting member 420 including an upper back end attached to the other end of the torsional spring 404, an upper front end attached to a cam wheel 422, and a lower end attached to a second clip member 424. The second clip member 424 includes a second lip 426 at its lower end for making contact to the other side of the flexible substrate S. The sides of the second clip member 424 are tapered, such that its upper end is wider than its lower end. A lower portion of the pivoting member 420 and the second clip member 424 extend substantially parallel with the fixed member 402 and the first clip member 406. The remaining portion of the pivoting member 420 extends upwardly at an acute angle with that of the fixed member 402.

The lower portion of the pivoting member 420 is also attached to a shield 428 used to improve the uniformity of the plating formed on the flexible substrate S. The shield 428 is attached to the lower end of the pivoting member 420, at approximately the region which the second clip member 424 is attached to the pivoting member 420. The shield 428 extends downward from that region to below the lower end of the clip members 424 and 406. The shield 428 is configured to completely laterally shield the clip members 424 and 406. It shall be understood that if both sides of the flexible substrate S were to be plated, there would also be a corresponding shield attached to the fixed member 402 at substantially the same location and with substantially the same position and orientation.

Without the shield 428, there would typically be a build up of plating near the point of contact of the clip 400 to the flexible substrate S. This is because the current density is typically much higher at that region. To reduce the current density at that region in order to better equalize the current density throughout the width of the flexible substrate S, the shield 428 operates to reduce the current density at the region for that purpose. It shall be understood that the configuration of the shield 428 may vary with the article undergoing plating, the plating solution, the specified current density, the configuration of the anode electrode, and other factors.

In operation, the torsional spring 404 biases the pivoting member 420 with respective to the fixed member 402 such that the clip 400 is in a normally closed position. The cam wheel 422 rides along a clip actuator (e.g., a rail) which controls the pivoting of the pivoting member 420 (against the bias force of the torsional spring 404) to provide the desired opening or closing of the clip 400 at designated regions along the movement of the clip 400. For example, the clip actuator may control the pivoting member 420 such that the clip 400 is in a closed position while it is engaged with the flexible substrate S during transportation through the electroplating system. When disengaging from the flexible substrate S, the clip actuator may control the pivoting member 420 such that the clip 400 is fully opened. When the clip 400 enters the clip strip cell, the clip actuator may control the pivoting member 420 such that the clip 400 is slightly opened. It shall be understood that the location of the opening and closing of the clip 400 along its movement, and the degree to which the clip 400 is opened may vary substantially depending on the particular processing strategy.

FIG. 5A illustrates a side view of an exemplary lower clip 500 in a closed position in accordance with another embodiment of the invention. The lower clip 500 comprises a fixed clip member 502 and a pivoting clip member 504 pivotable about a substantially horizontal axis. A torsional spring 506 positioned substantially coaxial with the pivot axis of the pivoting clip member 504 applies a biasing force to the pivoting clip member 504 such that the top portions of the fixed and pivoting clip members 502 and 504 are urged together to engage with the lower portion of the flexible substrate S. Thus, the biasing force of the torsional spring 506 sets the lower clip 500 in a normally-closed configuration. The pivoting clip member 504 further includes a cam surface adapted to engage with a clip actuator to control the opening and closing of the lower clip 500.

The lower portion of the lower clip 500 is attached to the lower support structure 252 b, which, in this example, is a belt. The substrate stability system further includes a belt guide 520 to guide the movement of the belt within the electroplating system. In particular, the belt guide 520 includes a narrow opening in which a lower portion of the belt 252 b is situated. The substrate stability system further includes a roller guide 522 to assist in the guiding of rollers connected to the lower belt to improve the vertical stability of the belt 252 b while it moves.

FIG. 5B illustrates a side view of the exemplary lower clip 500 in an open position in accordance with another embodiment of the invention. As previously discussed, the pivoting clip member 504 of the lower clip 500 includes a cam surface 508 adapted to engage with a clip actuator 540 in order to control the opening and closing of the lower clip 500 as desired. As shown in this figure, the clip actuator 540 has urged the cam surface 508 of the pivoting clip member 504 to cause the opening of the lower clip 500.

In operation, the clip actuator 540 acts to open the lower clip 500 to disengage the clip 500 from the lower portion of the flexible substrate S. This may be performed immediately upstream of the unloading station, or immediately upstream of the post-processing section, or at any other location pursuant to the processing strategy. In this example, the clip actuator 540 keeps the lower clip 500 in the open position until it is to be engaged again with the flexible substrate S near the loading station. Again, the clip actuator 540 may be configured to open and close the lower clip 500 as desired pursuant to the processing strategy.

FIG. 6 illustrates a side view of the exemplary upper and lower clips 400 and 500 engaged with the flexible substrate S in accordance with another embodiment of the invention. As shown, the upper clip 400 is adapted to engage with an upper portion of the flexible substrate S. In this example, the upper portion of the flexible substrate S is relatively small (e.g., seven (7) millimeters) as compared to the width W of the flexible substrate S. Similarly, the lower clip 500 is adapted to engage with a lower portion of the flexible substrate S. In this example, the lower portion of the flexible substrate S is also relatively small (e.g., seven (7) millimeters) as compared to the width W of the flexible substrate S. Having the upper and lower clips 400 and 500 contact only a relatively small portion of the flexible substrate S substantially maximizes the platable surface of the flexible substrate S.

FIGS. 7A-7C illustrate side, front, and top views of an exemplary seal 700 in accordance with another embodiment of the invention. The seal 700 may be an exemplary detailed version of the seals 205 a and 205 b discussed above with reference to the electroplating system 200. As previously discussed, the lower clips 254 b traverse a bottom portion of the fluid bath contained in the electroplating cell 206. To enter and exit the electroplating cell 206, the lower clips 254 b enter and exit through corresponding openings. Such openings are near the bottom of the fluid-containing cell 206. Accordingly, the seal 700 is configured to allow the passage of the lower clips through the openings, while reducing leakage of plating fluid from the electroplating cell 206.

For explanation purposes, the seal 700 shown is an exemplary detailed version of the input seal 205 a to the electroplating cell 206, and is situated between the pre-treatment cell 204 and the electroplating cell 206. It shall be understood that the seal 700 may also serve as the output seal 205 b of the electroplating cell 206. In particular, the seal 700 comprises an upper portion 702 and a lower portion 750. The upper portion 702 of the seal 700 is primarily configured to allow the passage of the top clips 254 a and the flexible substrate S into (and out of) the electroplating cell 206, while reducing leakage of plating fluid from the electroplating cell 206. The lower portion 750 of the seal 700 is primarily configured to allow the passage of the lower clips 254 b and the lower support structure 252 b into (and out of) the electroplating cell 206 while reducing leakage of plating fluid from the electroplating cell 206. The lower portion 750 of the seal 700 also assists in guiding the leaked plating fluid to the drain 206 a via a spill out area 770. The drain 206 a, in turn, routes the leaked plating fluid to a reservoir (not shown) to collect the fluid for recycling purposes.

The upper portion 702 of the seal 700 comprises support structures 704 a-b for supporting a plurality of opposed glass rods 708 a-b, 712 a-b, 716 a-b, and 720 a-b. More specifically, the support structure 704 a includes a plurality of rod supports 706 a, 710 a, 714 a, and 718 a including respective grooves to respectively receive the elongated cylindrical glass rods 708 a, 712 a, 716 a, and 720 a. The grooves of the rod supports 706 a, 710 a, 714 a, and 718 a are configured to expose the center sides (i.e., the sides facing the flexible substrate) of the elongated cylindrical glass rods 708 a, 712 a, 716 a, and 720 a. The support structure 704 b, in turn, includes a plurality of rod supports 706 b, 710 b, 714 b, and 718 b including respective grooves to respectively receive the elongated cylindrical glass rods 708 b, 712 b, 716 b, and 720 b. The grooves of the rod supports 706 b, 710 b, 714 b, and 718 b are configured to expose the center sides (i.e., the sides facing the flexible substrate) of the elongated cylindrical glass rods 708 b, 712 b, 716 b, and 720 b.

This configuration defines elongated gaps between opposed glass rods 708 a-b, 712 a-b, 716 a-b, and 720 a-b, respectively. The elongated gaps are configured to allow the passage of the flexible substrate S therethrough, while reducing contact of the flexible substrate S to the glass rods. That is, the elongated gaps are configured such that leaked plating fluid situated between the rods and the flexible substrate S further inhibits the flexible substrate S from contacting the rods in order to reduce contact damages to the flexible substrate S. As discussed, the rods are made of glass material or other non-scratching material, which reduces or eliminates surface damage to the flexible substrate S in case the substrate S makes contact with the rods. 0065

The first three sets of rods 708 a-b, 712 a-b, and 716 a-b (from the left as shown) are inclined such that their upper portions are situated further downstream along the movement of the flexible substrate S than their respective lower portions. This makes it more difficult for plating fluid to leak through the elongated gaps. The fourth set of rods 720 a-b (from the left as shown) is oriented substantially vertical to provide a vertical interface to the electroplating cell 206. As shown in FIG. 7B, the support structures 704 a-b be are recessed near the top to define a groove 722 through which the upper clips 254 b travel.

The lower portion 750 of the seal 700 includes a chamber 752 having a lower opening 754. The chamber 752 includes an inlet 756 to receive the incoming lower clips 254 b, and an outlet 758 to allow the lower clips 254 b to pass through into the electroplating cell 206. Situated inside the chamber 752 is a first set of opposed doors 760 a-b (e.g., similar to saloon doors). The doors 760 a-b are spring biased against an inside wall of the chamber 752 to normally occlude the inlet 756. Situated on the outside of the chamber 752 is a second set of doors 762 a-b (e.g., similar to saloon doors). The doors 762 a-b are spring biased against an outside wall of the chamber 752 to normally occlude the outlet 758. As discussed in further detail below, the movement of the lower clips 254 b forces the doors to open. The lower portion 750 of the seal 700 further includes a buffer area 764 to allow the doors 762 a-b to swing outwardly without penetrating the electroplating cell 206.

In operation, as the flexible substrate S is being transported through the seal 700, the flexible substrate S moves through the elongated gaps between the respective opposed glass rods 708 a-b, 712 a-b, 716 a-b, and 720 a-b. The fourth set of glass rods 720 a-b operate to perform a first stage seal. Some plating fluid from the electroplating cell 206 leaks through the fourth set of rods 720 a-b as represented by the four (4) arrows as depicted in FIG. 7A. The third set of glass rods 716 a-b operate to perform a second stage seal. Less plating fluid leaks through the rods 716 a-b as represented by the three (3) arrows depicted in FIG. 7B. The remaining sets of rods 712 a-b and 708 a-b operate as third and fourth seal stages to further reduce leakage; two (2) arrows shown through rods 712 a-b and one (1) arrow shown through rods 708 a-b. Thus, only a relatively small amount of plating fluid leaks through the rods 708 a-b. The leakage of plating fluid through the rods 708 a-b, 712 a-b, 716 a-b, and 720 a-b flows down to the spill out area 770 directly and through the chamber 752 of the lower portion 750 of the seal 700.

With reference to FIGS. 7D-F, as a lower clip 254 b enters the seal 700, the movement of the lower clip 254 b forces the first set of doors 760 a-b to open, while the second set of doors 762 a-b remain closed. When the lower clip 254 b moves passed the doors into the chamber 752, the spring bias of the doors 760 a-b forces the doors closed. In this state, both sets of doors 760 a-b and 762 a-b are in their closed position, thereby substantially reducing or eliminating leakage from the electroplating cell 206. The lower clip 254 b then moves further and forces the second set of doors 762 a-b to open. In this state, plating fluid from the electroplating cell 206 leaks into the chamber 752 by way of the outlet 758. Also, in this state, the first set of doors 254 b are in their closed position, thereby substantially reducing or eliminating leakage of plating fluid through the inlet 756. The leaked plating fluid flows down into the lower opening 754 of the chamber 752, and subsequently to the spill out area 770 and drain 206 a.

After the lower clip 254 b moves pass the second set of doors 762 a-b, the spring bias of the doors 762 a-b forces the doors 762 a-b in their closed position. In this state, both sets of doors 760 a-b and 762 a-b remain closed. Then, the next lower clip 254 b moves to open the first set of doors 760 a-b, and sealing cycle is repeated. Thus, at any given time, at least one set of doors is closed in order to reduce of plating fluid through the seal 700.

Although the various embodiments of the invention have been described with reference to performing an electroplating process, it shall be understood that these embodiments may be configured for implementing other types of processes including electroless plating, developing, stripping, cleaning, and others. In addition, although the various embodiments have been described with reference to performing a process on a flexible substrate, it shall be understood that the embodiments may be configured to process other types of articles.

While the invention has been described in connection with an exemplary embodiment, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains. 

1. A processing system for plating a flexible substrate, comprising: a loading station including an input spool adapted to support a wounded, unprocessed flexible substrate; a processing station adapted to perform a predetermined process on said flexible substrate, while said flexible substrate is in a substantially vertical orientation; an unloading station including an output spool adapted to support a wounded, processed flexible substrate; and a substrate stability subsystem adapted to maintain said flexible substrate in a substantially vertical orientation while said flexible substrate undergoes said predetermined process in said processing station.
 2. The processing system of claim 1, wherein said substrate stability subsystem is adapted to apply substantially vertical tension on said flexible substrate.
 3. The processing system of claim 1, wherein said substrate stability subsystem comprises: a plurality of upper clips adapted to engage with an upper portion of said flexible substrate; and a plurality of lower clips adapted to engage with a lower portion of said flexible substrate.
 4. The processing system of claim 3, wherein said substrate stability subsystem further comprises: an upper movable support structure adapted to support said, upper clips; and a lower movable support structure adapted to support said lower clips.
 5. The processing system of claim 4, wherein said upper movable support structure comprises a belt, cable, or belt.
 6. The processing system of claim 4, wherein said lower movable support structure comprises a belt, cable, or belt.
 7. The processing system of claim 4, wherein said substrate stability subsystem further comprises: an upper idle wheel; an upper drive wheel; and a motor rotationally coupled to said upper drive wheel; wherein said upper movable support structure is rotationally supported around said upper idle and drive wheels.
 8. The processing system of claim 4, wherein said substrate stability subsystem further comprises: a lower idle wheel; a lower drive wheel; and a motor rotationally coupled to said lower drive wheel; wherein said lower movable support structure is rotationally supported around said lower idle and drive wheels.
 9. The processing system of claim 3, wherein said substrate stability subsystem further comprises an upper clip actuator adapted to open and close said upper clips at different predetermined locations.
 10. The processing system of claim 9, wherein each of said upper clips comprises a cam wheel adapted to engage with said upper clip actuator.
 11. The processing system of claim 3, wherein said substrate stability subsystem further comprises a lower clip actuator adapted to open and close said lower clips at different predetermined locations.
 12. The processing system of claim 11, wherein each of said lower clips comprises a cam surface adapted to engage with said lower clip actuator.
 13. The processing system of claim 9, wherein said upper clip actuator is adapted to close said upper clips to engage with said flexible substrate at a first location upstream of a second location where a lower clip actuator is adapted to close said lower clips to engage with said flexible substrate.
 14. The processing system of claim 9, wherein said upper clip actuator and a lower clip actuator are adapted to respectively open said upper and lower clips to disengage from said flexible substrate at substantially the same time.
 15. The processing system of claim 3, wherein said upper clips are each adapted to apply a cathode contact to said flexible substrate.
 16. The processing system of claim 15, further comprising a clip strip cell adapted to remove processing material off of said upper clips.
 17. The processing system of claim 3, wherein said lower clips are each adapted to apply a cathode contact to said flexible substrate.
 18. The processing system of claim 17, further comprising a clip strip cell adapted to remove processing material off of said lower clips.
 19. The processing system of claim 3, wherein each of said upper clips comprises a shield configured to improve a uniformity of material deposition across said flexible substrate.
 20. The processing system of claim 3, wherein each of said lower clips comprises a shield configured to improve a uniformity of material deposition across said flexible substrate.
 21. The processing system of claim 3, wherein said processing station comprises a container adapted to support a bath of fluid, wherein said container includes an opening adapted to pass therethrough said lower clips.
 22. The processing system of claim 21, wherein said container further comprises a seal to reduce leakage of fluid from said container through said opening, while allowing said lower clips to pass through said opening.
 23. The processing system of claim 22, wherein said seal comprises: a door that swivels about an axis; and a biasing device adapted to bias said door against said container to occlude said opening, wherein said lower clips are each adapted to force said door away from said container against said bias as each clip enters or exits said container.
 24. The processing system of claim 22, wherein said seal comprises: a first door that swivels about a first axis; a second door that swivels about a second axis; a first biasing device adapted to bias said first door against said container to occlude a first portion of said opening; and a second biasing device adapted to bias said second door against said container to occlude a second portion of said opening; wherein said lower clips are each adapted to force said first and second doors away from said container against said first and second biases as each clip enters or exits said container.
 25. The processing system of claim 1, wherein said processing station comprises an electroplating cell.
 26. The processing system of claim 1, wherein said processing station comprises a pre-treatment cell.
 27. The processing system of claim 26, wherein said pre-treatment cell is adapted to perform alkaline and/or acid cleaning of said flexible substrate.
 28. The processing system of claim 26, wherein said pre-treatment cell is adapted to perform a de-ionized water rinse of said flexible substrate.
 29. The processing system of claim 1, wherein said processing station comprises a post-treatment cell.
 30. The processing system of claim 29, wherein said post-treatment cell is adapted to perform an anti-tarnish rinse of said flexible substrate.
 31. The processing system of claim 29, wherein said post-treatment cell is adapted to perform a de-ionized water rinse of said flexible substrate.
 32. The processing system of claim 29, wherein said post-treatment cell is adapted to perform a drying of said flexible substrate.
 33. A method of processing a flexible substrate, comprising transporting said flexible substrate into and out of a processing cell, while applying substantially vertical tension to said flexible substrate to maintain said flexible substrate in a substantially vertical orientation while said substrate is undergoing a process performed by said processing cell.
 34. A processing system for processing an article, comprising: a processing station adapted to perform a predetermined process on said article, while said article is in a substantially vertical orientation; and an article stability subsystem adapted to apply substantially vertical tension to said article to maintain said article in a substantially vertical orientation while said article is undergoing a process performed by said processing station.
 35. An electroplating apparatus for plating a moving article, comprising: an electroplating cell including: a container to support a bath of plating fluid; and an anode electrode situated within said container and adapted to contact said bath of plating fluid; and a cathode contact system comprising a plurality of movable clips adapted to make continuous cathode contact with said moving article, wherein each of said clips comprises a shield configured to improve a uniformity of a plating deposition formed on said article.
 36. The electroplating apparatus of claim 35, wherein each of said shield is adapted to reduce a plating current density flowing through said article proximate a region where said corresponding clip makes contact to said article.
 37. An apparatus for processing a moving article, comprising: an article stability system comprising a plurality of movable clips adapted to engage lower portions of said moving article to maintain said moving article in a substantially vertical orientation; a processing cell including a container adapted to support a bath of processing fluid; and a first seal, comprising: a first chamber to receive processing fluid leaked from said processing cell; a first inlet through which said movable clips are allowed to pass into said first chamber; a first inlet occluding device adapted to occlude said first inlet; a first outlet through which said movable clips are allowed to pass out of said first chamber; and a first outlet occluding device adapted to occlude said first outlet.
 38. The apparatus of claim 37, wherein said first chamber is adapted to receive said leaked processing fluid by way of said first outlet.
 39. The apparatus of claim 37, wherein said first chamber is adapted to receive said leaked processing fluid by way of said first inlet.
 40. The apparatus of claim 37, wherein said first occluding device comprises a door biased against a wall of said first chamber to occlude said first inlet, wherein said lower clips are each adapted to force said door away from said wall against said bias as each clip passes through said first inlet.
 41. The apparatus of claim 37, wherein said first occluding device comprises: a first door that swivels about a first axis; a second door that swivels about a second axis; a first biasing device adapted to bias said first door against a wall of said first chamber to occlude a first portion of said first inlet; and a second biasing device adapted to bias said second door against said wall of said first chamber to occlude a second portion of said first inlet; wherein said lower clips are each adapted to force said first and second doors away from said wall of said first chamber against said first and second biases as each clip passes through said first inlet.
 42. The apparatus of claim 37, wherein said first outlet occluding device comprises a door biased against a wall of said first chamber to occlude said first outlet, wherein said lower clips are each adapted to force said door away from said wall against said bias as each clip passes through said first outlet.
 43. The apparatus of claim 37, wherein said first outlet occluding device comprises: a first door that swivels about a first axis; a second door that swivels about a second axis; a first biasing device adapted to bias said first door against a wall of said first chamber to occlude a first portion of said first outlet; a second biasing device adapted to bias said second door against said wall of said first chamber to occlude a second portion of said first outlet; wherein said lower clips are each adapted to force said first and second doors away from said wall of said chamber against said first and second biases as each clip passes through said first outlet.
 44. The apparatus of claim 37, further including a second seal comprising: a second chamber to receive processing fluid leaked from said processing cell; a second inlet through which said movable clips are allowed to pass into said second chamber; a second inlet occluding device adapted to occlude said second inlet; a second outlet through which said movable clips are allowed to pass out of said second chamber; and a second outlet occluding device adapted to occlude said second outlet; wherein said first chamber is adapted to receive said leaked processing fluid by way of said first outlet, and wherein said second chamber is adapted to receive said leaked processing fluid by way of said second inlet.
 45. The apparatus of claim 37, wherein said first chamber includes an opening through which said leaked processing fluid flows to a drain.
 46. The apparatus of claim 45, wherein said leaked processing fluid flows to said drain by way of a spill out area.
 47. The apparatus of claim 37, wherein said first seal includes a structure including an elongated opening through which said flexible substrate pass.
 48. The apparatus of claim 47, wherein said structure includes a pair of opposed rods, wherein a spacing between said opposed rods defines said elongated opening.
 49. The apparatus of claim 48, wherein said opposed rods are made of glass material.
 50. The apparatus of claim 48, wherein said opposed rods are inclined such that an upper portion thereof lies further downstream along a direction of movement of said article than a lower portion thereof.
 51. The apparatus of claim 37, wherein said structure includes a plurality of sets of opposed rods spaced apart from each other along a direction of movement of said article, wherein a spacing between each of said opposed rods define said elongated opening.
 52. The apparatus of claim 51, wherein at least one set of said opposed rods is inclined such that an upper portion thereof lies further downstream along said direction of movement of said article than a lower portion thereof.
 53. The apparatus of claim 51, wherein at least one set of said opposed rods is in a substantially vertical orientation. 